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Humidity and its Influence on Interfaces and Surfaces DataPhysics Instruments Logo

Humidity and its Influence on Interfaces and Surfaces

Figure 1: Fogged-up glasses demonstrate how humidity causes condensation on surfaces. Precise humidity control in laboratories is crucial for developing coatings and materials that minimize condensation, ensuring fog-free surfaces.

Figure 1: Fogged-up glasses demonstrate how humidity causes condensation on surfaces. Precise humidity control in laboratories is crucial for developing coatings and materials that minimize condensation, ensuring fog-free surfaces.

Humidity describes the amount of water in the air. It influences physical processes, chemical reactions, and biological systems. That is why controlled adjustment and measurement of humidity is so important when analyzing surface parameters such as wetting.

Humidity as an interface parameter

Humidity describes the amount of water in the air and indicates how much water is contained in the atmosphere in gaseous form. A distinction is made between absolute and relative humidity. Absolute humidity refers to the actual amount of water in a given volume of air and is usually expressed in grams per cubic meter. Relative humidity, on the other hand, describes the ratio of the amount of water currently contained to the maximum possible amount of water that the air can hold at a given temperature. Relative humidity is expressed as a percentage. Since warm air can absorb significantly more water than cold air, relative humidity is highly dependent on temperature. When air cools, relative humidity rises until the saturation point is reached. At this point, condensation begins and dew or fog form.

Influence of air humidity on physical and chemical processes at interfaces

Humidity has a significant influence on processes at interfaces. It is therefore advantageous to include humidity as a controlled parameter in relevant measurements. A prominent example is adsorption. Depending on the humidity, adsorption can be promoted or prevented. The presence of moisture in the air can catalyze or inhibit chemical reactions at interfaces. Corrosion of metals, hydrolysis of materials and the formation of oxide films are just a few examples. On biological materials, humidity can lead to swelling.

Regulation of humidity in the laboratory environment

The humidity generators and controllers in the HGC series from DataPhysics Instruments can be used to control the relative humidity inside measuring chambers. In combination with a measuring device from DataPhysics Instruments, this allows the influence of air humidity on interface parameters to be investigated.

An example: Moss or mold growth on facades is an unsightly problem that occurs particularly in conditions of high and prolonged humidity. To investigate which surface properties promote the fastest possible drying, the high humidity associated with the formation of morning dew can be simulated using a humidity generator from the HGC series.

The HGC series humidity generators are stand-alone devices that can be combined with a wide range of laboratory equipment and chambers from other manufacturers. The HGC series is also available as an OEM product. For example, Verpaalen et al. were able to use an HGC 30 to investigate a nature-inspired double layer that changes its curvature depending on temperature and humidity.

Other areas of application for the use of a humidity generator and controller from the HGC series include:

  • atomic force microscopy (AFM)
  • dynamic mechanical analysis (DMA)
  • isothermal microcalorimetry (IMC)
  • near infrared spectroscopy (NIR)
  • Raman microscopy
  • rheology
  • thermogravimetric analysis (TGA)
  • thermomechanical analysis (TMA)
  • X-ray diffraction (XRD)
  • various chambers and enclosures by DataPhysics Instruments